1. Field of the invention
The present invention relates to a tool holder, more particularly one, which will prevent the tool from getting damaged and broken in vibration during a machining process, and allows the tool to be used repeadedly.
2. Brief Description of the Prior Art
Advanced lathes are available for performing precision machining operation with progress of technology. Tools are usually held on tool holders of lathes in such a way as to be easily changed.
A conventional tool holder includes a tool holder main part, and an angular pressing member. The tool holder main part has a fitting portion at a rear end, and a tool holding portion adjacent to the fitting portion; the fitting portion has a screw hole on a bottom, and a propping portion protruding on a rear end; the tool holding portion has a connecting hole on a bottom thereof. A plate-shaped tool is positioned on a pad, and screwed onto the tool holding portion by means of a bolt, which is passed through the connecting hole. The angular pressing member is positioned on a C-shaped ring, and screwed onto the fitting portion of the main part by means of a fixing screw, which is passed though the angular member and into the screw hole; thus, the angular pressing member is pressed against a rear portion of the plate-shaped tool, and closely in touch with the propping portion of the fitting portion of the main part at rear a rear edge thereof. Therefore, the propping portion of the main part will prop the angular pressing member, which will be subjected to rearward force in a machining operation.
However, the above tool holder has the following disadvantages:
1. The plate-shaped tool is prone to get damaged and even broken in vibration during a machining operation because the angular pressing member is only pressed against a small portion of a rear end of the plate-shaped tool.
2. The plate-shaped tool will hit a corner of the tool holding portion of the tool holder main part during a machining operation. Consequently, the plate-shaped tool wears very rapidly, and the service life is reduced, causing increase to the manufacturing cost.